Definitely
The Blue Max. I especially liked the scenes with the Pfalz replicas, and the DVIIs weren't bad, either. The dogfight scenes were entertaining, and the storyline was also well done. Very underrated film, IMO.
Flyboys, while entertaining and thought provoking, was not the best one I've seen, but it satisfied me (especially because there are few movies about World War I aviation out now). I was not pleased with seeing all the DR1s (let alone since 99% of them were all red), but I can understand where the director was going (the DR1 is easily the most identifiable German plane of the war to even non-aviation enthusiasts; makes it easier for the audience to identify who is who).
I have not seen
Aces High, so I can't make an honest comment on it.
I stick to the old films like
Wings,
Hell's Angels,
The Dawn Patrol, etc. Some of them are a bit corny at times, but seeing AUTHENTIC planes that were leftover from the Great War is stunning to me, and given that the dogfighting scenes were using real planes makes me even more excited.
To be honest, I do not care for all the CGI crap of today. It makes reality and fiction come together too easily, I think. CGI planes do not and will never behave like the real thing.